نتایج جستجو برای: cosmic ray

تعداد نتایج: 325747  

1996
Günter Sigl Sangjin Lee Paolo Coppi

The isotropic component of the γ-ray flux between 100MeV and 100EeV (10 eV) contains important information about the origin of highest energy cosmic rays and the extragalactic magnetic field (EGMF). Using numerical simulations of extragalactic cosmic and γ-ray propagation we show that an average fraction of ≃ 10% γ-rays in the total cosmic ray flux around 10EeV would imply both a non-accelerati...

1997
R. Schlickeiser

Evidence for the possible existence of a strong flux of low-energy (< 10 MeV) cosmic ray electrons in the Galaxy has been recently established by GINGA, OSSE and COMPTEL observations of the diffuse galactic gamma ray continuum emission down to photon energies below 50 keV. We explain the implied presence of many low-energy cosmic ray electrons with the existence of interstellar in-situ reaccele...

2013
R. BHATTACHARYA

Cosmic ray causes hazards to microelectronic circuits. Presence of charged particles in the atmosphere was first noticed by Coloumb in 1785. But cosmic ray was discovered by Victor Hess in 1912. However new era of particle physics was started with the invention of neutron monitor in 1948 by John A. Simpson. New information regarding the energy spectrum, anisotropy, latitudinal, longitudinal and...

2008
Jacek Niemiec

We present results of twoand three-dimensional Particle-In-Cell simulations of magnetic-turbulence production by isotropic cosmic-ray ions drifting upstream of supernova remnant shocks. The studies aim at testing recent predictions of a strong amplification of short-wavelength non-resonant wave modes and at studying the subsequent evolution of the magnetic turbulence and its backreaction on cos...

2008
P Sommers

Cosmic ray astronomy attempts to identify and study the sources of ultrahigh energy cosmic rays. It is unique in its reliance on charged particles as the information carriers. While no discrete source of ultrahigh energy cosmic rays has been identified so far, a new generation of detectors is acquiring the huge exposure that is needed at the highest energies, where deflection by magnetic fields...

2008
V. I. Zatsepin N. V. Sokolskaya

Aims. A model to describe cosmic ray spectra in the energy region from 10 11 up to 10 17 eV is suggested. It bases on the preposition that Galactic cosmic ray flux is a mixture of fluxes, accelerated by shocks from nova and supernova explosions of different types. Methods. We analyze recent experimental data on cosmic ray spectra obtained in direct measurements above the atmosphere and data obt...

2008
G. E. Allen E. V. Gotthelf R. Petre

Analyses of the X-ray data of the five young shell-type supernova remnants Cas A, Kepler, Tycho, SN 1006, and RCW 86 suggest that some of the X-ray emission of these sources is non-thermal. This non-thermal emission is qualitatively consistent with models of the broad-band (radio-to-X-ray) synchrotron spectra of remnants and does not seem to be consistent with other non-thermal X-ray emission p...

2008
JOHN E. EVERETT ELLEN G. ZWEIBEL

We apply a wind model, driven by combined cosmic-ray and thermal-gas pressure, to the Milky Way, and show that the observed Galactic diffuse soft X-ray emission can be better explained by a wind than by previous static gas models. We find that cosmic-ray pressure is essential to driving the observed wind. Having thus defined a “best-fit” model for a Galactic wind, we explore variations in the b...

2002
K. Mursula I. G. Usoskin G. A. Kovaltsov

It was recently suggested (Lockwood, 2001) that the cosmic ray intensity in the neutron monitor energy range is linearly related to the coronal source flux, and can be reconstructed for the last 130 years using the long-term coronal flux estimated earlier. Moreover, Lockwood (2001) reconstructed the coronal flux for the last 500 years using a similar linear relation between the flux and the con...

2004
K. Scherer S. E. S. Ferreira

In this paper we present a new five particle species hybrid model for calculating cosmic ray particle transport and acceleration in a dynamic heliospheric environment. In particular the effects of solar cycle related changes in the solar wind speed on the heliospheric geometry, solar wind flow and cosmic ray distribution are discussed, when a polarecliptic asymmetry at the inner boundary is mod...

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